Study news hits Amgen

Amgen Inc. said Friday that interim results from an independent study involving breast cancer patients found its anemia drug Aranesp did not enhance the effect of chemotherapy before surgery.

Amgen shares, which closed at $55.25, down 21 cents, fell 4% to $53 in extended trading as the company also reported preliminary follow-up data showing more deaths and reports of tumor growth among patients who received Aranesp than among those in the control group.

The Thousand Oaks-based company cautioned that the results -- which land amid concerns about the overuse and safety of the anemia drug class -- were preliminary and said no conclusions should be drawn until the final study report was completed.

The study, involving 733 patients, was designed to evaluate whether Aranesp prevented anemia and augmented the therapeutic effects of the chemotherapy regimens, Amgen said.

The study was conducted by the German Gynecological Oncology Study Group and the German Breast Group.